This protocol is designed to test 2 hypotheses: 1) that diet can effect plasma nitrite and nitrate measurements in a predictable way; and 2) that changes in nitric oxide production locally during reactive hypercalcemia can be detected as acute changes in nitrite and nitrate levels. The GCRC staff provided logistics for randomization and all blood work. The GCRC dietitian and research kitchen provided meals. The brachial ultrasound measurements were performed in the Cardiology Clinic by an ECHO technician. Blood samples were frozen and stored at -80 degrees for nitrate and nitrite analysis. After 5 patients, the protocol was put on hold for two reasons: 1) data from the American Heart Association meeting suggested a different method of collecting nitrite and nitrate samples; and 2) blood drawing procedure during brachial ultrasound. We intend to reopen the study and complete recruitment in early 2000.